Thesis (M.Sc.)--Memorial University of Newfoundland. / Typescript. Bibliography: leaves 142-147. Also available online.

Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-06Bitstream added on 2014-06-13T20:18:25Z : No. of bitstreams: 1 souzafilho_mp_me_guara.pdf: 3830984 bytes, checksum: 7c2960cef5b04e4cbf20952bbc3f0443 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo o desenvolvimento das técnicas fundição de semicubos do trem de pouso principal do cargueiro C-115 Buffalo da Força Área Brasileira, pelo processo de fundição de liga de magnésio em moldes de areia a verde para atender as necessidades emergenciais nas atividades de apoio logístico, tático e transporte. Por ser um item estrutural cujas exigências em relação às propriedades de engenharia e segurança são rigorosas, foi necessário o desenvolvimento de técnicas de fundição diferenciadas para a obtenção do modelo com suas respectivas superespessuras de contração e usinagem; ângulos de saída; sistemas especiais de canais de alimentação; molde preparado com areia sintética, bentonita, enxofre, ácido bórico e água; magnésio, alumínio, zinco e alumínio-manganês de grau metalúrgico para a obtenção da liga; tratamento e refino do banho metálico, técnica de vazamento com frentes de alimentação simétricas; controle de qualidade por meio de inspeção visual, análise da composição química e metalográfica das fases e constituintes da liga, ensaios mecânicos e radiográficos para qualificação do fundido, conforme padrões aeronáuticos. Os ensaios apresentaram resultados cujos valores obtidos foram comparados com os padrões aeronáuticos internacionais, permitindo viabilizar a transferência desse desenvolvimento para o processo produtivo de forma a atender necessidades emergenciais e estimular a evolução do setor aeronáutico do País. / This work had as objective the development of the techniques of semicubes casting of the main landing gear of the C-115 Buffalo freighterm from Brazilian Air Force, by the process of magnesium alloy casting in green sand molds to attend to the emergent necessities in the activities of logistic, tactical support and air service. The creation of the Project of Nationalization of Aeronautical Components was necessary for the maintenance of the operationalization of the aircraft and to prevent the collapse of the fleet. Aeronautical wells are a structural item whose requirements in relation to the security and engineering properties are rigorous, it was necessary the development of differentiated techniques of casting for the attainment of the model with its respective superthicknesses contraction adn machining; pattern draft; special gate systems; mold prepared in synthetic sand, bentonite sand, sulphur, acid boric and water; magnesium, aluminium, zinc and aluminum-manganese of metallurgical degree for obtention of the alloy; treatment and refining of the metallic bath, pouring technique with symmetrical fronts of feeding; quality control by means of visual inspection, analysis of the chemical and metallographic composition of the phase and mechanical and radiografic constuent of the alloy, assays for qualification of the casting, as aeronautical standards. The assays had presented resulted whose gotten values had been compared with international aeronautical standards, allowing to make possible the transference of this devolopment for the productive process to pay attention to emergency necessities and to stimulate the evolution of the aeronautical sector of the Country.

La conception des moteurs aéronautiques est soumise à de nombreuses contraintes telles que les gains de performance ou les normes environnementales de plus en plus exigeantes. Face à ces objectifs souvent contradictoires, les nouvelles technologies de moteur tendent vers une augmentation de la température locale et globale dans les étages chauds. En conséquence, les parties solides comme les parois du brûleur sont soumises à des niveaux de température élevés ainsi que d’importants gradients de température, tous deux critiques pour la durée de vie du moteur. Il est donc essentiel pour les concepteurs de caractériser précisément la thermique locale de ces systèmes. Aujourd’hui, la température de paroi est évaluée par des essais de coloration. Pour limiter ces essais relativement chers et complexes, des outils numériques haute fidélité capables de prédire la température de paroi des chambres de combustion sont actuellement développés. Cet exercice nécessite de considérer tous les modes de transfert de chaleur (convection, conduction et rayonnement) ainsi que la combustion au sein du brûleur. Ce problème multi-physique peut être résolu numériquement à l’aide de différentes approches numériques. La méthode utilisée dans ce travail repose sur une approche partitionnée qui inclut la résolution de l’écoulement turbulent réactif par un code de simulation aux grandes échelles (LES), un solveur radiatif basé sur la méthode aux ordonnées discrètes ainsi qu’ un code de conduction solide.Les diverses questions et difficultés liées à la répartition des ressources informatiques ainsi qu’à la méthodologie de couplage employée pour traiter les disparités d’échelles de temps et d’ espace présentes dans chacun des modes de transfert de chaleur sont discutées. La performance informatique des applications couplées est étudiée à travers un modèle très simplifié ainsi que sur une application industrielle. Les paramètres importants sont identifiés et des pistes potentielles d’amélioration sont proposées. La méthodologie de couplage thermique est ensuite étudiée du point de vue physique sur deux configurations distinctes. Pour commencer, l’équilibre thermique entre un fluide réactif et un solide est étudié pour une configuration académique d’accroche flamme. L’influence de la température de paroi de l’accroche flamme sur la stabilisation de flamme est mise en évidence sur des simulations fluideseul. Ces résultats indiquent trois états d’équilibre théorique différents. La pertinence physique de ces trois états est ensuite évaluée à l’aide de diverses simulations de transfert de chaleur conjugué réalisées pour différentes solutions initiales et conductivités solides. Les résultats indiquent que seulement deux états d’équilibre ont un sens physique et que la bifurcation entre les deux états possibles dépend à la fois de la condition initiale et de la conductivité solide. De plus, pour la gamme de paramètres testés, la méthodologie de couplage n’a pas d’effet sur les solutions obtenues. Une méthodologie similaire est ensuite appliquée à une chambre de combustion d’hélicoptère pour laquelle le rayonnement est de plus pris en compte. Diverses simulations sont présentées afin d’évaluer l’impact de chacun des processus de transfert de chaleur sur le champ de température : une simulation fluide-seul adiabatique de référence, de transfert de chaleur conjugué, d’interaction thermique fluide-rayonnement ainsi qu’une simulation incluant toutes les physiques. Ces calculs montrent la faisabilité d’un couplage LES/conduction solide dans un contexte industriel et fournissent de bonnes tendances de distribution de température. Pour finir, pour cette géométrie de brûleur et la condition d’opération simulée, les divers résultats montrent que le rayonnement joue un rôle important dans la distribution des températures de paroi. De ce fait, les comparaisons aux essais de coloration sont globalement en meilleur accord quand les trois modes de transfert sont pris en compte / The design of aeronautical engines is subject to many constraints that cover performance gain as well as increasingly sensitive environmental issues. These often contradicting objectives are currently being answered through an increase in the local and global temperature in the hot stages of the engine. As a result, the solid parts encounter very high temperature levels and gradients that are critical for the engine lifespan. Combustion chamber walls in particular are subject to large thermal constraints. It is thus essential for designers to characterize accurately the local thermal state of such devices. Today, wall temperature evaluation is obtained experimentally by complex thermocolor tests. To limit such expensive experiments, efforts are currently performed to provide high fidelity numerical tools able to predict the combustion chamber wall temperature. This specific thermal field however requires the consideration of all the modes of heat transfer (convection, conduction and radiation) and the heat production (through the chemical reaction) within the burner. The resolution of such a multi-physic problem can be done numerically through the use of several dedicated numerical and algorithmic approaches. In this manuscript, the methodology relies on a partitioned coupling approach, based on a Large Eddy Simulation (LES) solver to resolve the flow motion and the chemical reactions, a Discrete Ordinate Method (DOM) radiation solver and an unsteady solid conduction code. The various issues related to computer resources distribution as well as the coupling methodology employed to deal with disparity of time and space scales present in each mode of heat transfer are addressed in this manuscript. Coupled application high performance studies, carried out both on a toy model and an industrial burner configuration evidence parameters of importance as well as potential path of improvements. The thermal coupling approach is then considered from a physical point of view on two distinct configurations. First, one addresses the impact of the methodology and the thermal equilibrium state between a reacting fluid and a solid for a simple flame holder academic case. The effect of the flame holder wall temperature on the flame stabilization pattern is addressed through fluid-only predictions. These simulations highlight interestingly three different theoretical equilibrium states. The physical relevance of these three states is then assessed through the computation of several CHT simulations for different initial solutions and solid conductivities. It is shown that only two equilibrium states are physical and that bifurcation between the two possible physical states depends both on solid conductivity and initial condition.Furthermore, the coupling methodology is shown to have no impact on the solutions within the range of parameters tested. A similar methodology is then applied to a helicopter combustor for which radiative heat transfer is additionally considered. Different computations are presented to assess the role of each heat transfer process on the temperature field: a reference adiabatic fluid-only simulation, Conjugate Heat Transfer, RadiationFluid Thermal Interaction and fully coupled simulations are performed. It is shown that coupling LES with conduction in walls is feasible in an industrial context with acceptable CPU costs and gives good trends of temperature repartition. Then, for the combustor geometry and operating point studied, computations illustrate that radiation plays an important role in the wall temperature distribution. Comparisons with thermocolor tests are globally in a better agreement when the three solvers are coupled.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-10-10T13:29:21Z No. of bitstreams: 1 DissTKK.pdf: 6363757 bytes, checksum: c18f1887d457c1920bc3a2ff568e2f25 (MD5) / Approved for entry into archive by Ronildo Prado (producaointelectual.bco@ufscar.br) on 2017-10-10T17:27:10Z (GMT) No. of bitstreams: 1 DissTKK.pdf: 6363757 bytes, checksum: c18f1887d457c1920bc3a2ff568e2f25 (MD5) / Approved for entry into archive by Ronildo Prado (producaointelectual.bco@ufscar.br) on 2017-10-10T17:27:20Z (GMT) No. of bitstreams: 1 DissTKK.pdf: 6363757 bytes, checksum: c18f1887d457c1920bc3a2ff568e2f25 (MD5) / Made available in DSpace on 2017-10-10T17:31:49Z (GMT). No. of bitstreams: 1 DissTKK.pdf: 6363757 bytes, checksum: c18f1887d457c1920bc3a2ff568e2f25 (MD5) Previous issue date: 2015-06-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The improvement in the delivery reliability performance in Make-To-Order (MTO) companies has been becoming an important competitive criterion in the recent market context. Thus, it gets clear the importance of researches able to present tools to help the identification of enhancement opportunities in the matter of delivery reliability. The identification of opportunities requires a structure of diagnosis of the recent situation. However, depending on the performance problem to be diagnosed, a theoretical understructure based on specific scientific knowledge is needed. This work presents the framework developed by Soepenberg et al. (2012c) based on Workload Control (WLC) concepts. Such framework is composed by a structure for the diagnosis process of the reliability performance that allows browsing from the obtained performance to the subjacent causes related to Production Planning and Control (PPC). The aim of the present work is to present the WLC as well as the diagnostic tools with the purpose of elucidating their applicability through the framework developed by Soepenberg et al. (2012c) in a real context through a case study. The results of the case study indicated that the framework is a key instrument for diagnosis due to the accuracy by which it defines the causes of delays of the orders related to the PPC decisions. The application of the framework indicated that the lack of spare parts is the most impacting factor on delays, however this is not a cause only related to the company PPC decisions, but to external factors that are out of the company’s reach. Another result obtained is the verification that most of the orders are concluded before the date set. This is due to the lack of accuracy in the definition of the delivery dates and to the estimative mistakes of the capacity to be used for the maintenance of each part number, whose responsibilities rely on PPC. / A melhoria no desempenho da confiabilidade de entrega em empresas Make-To-Order (MTO) vem se tornando um importante critério competitivo na atual conjuntura de mercado. Diante do exposto, fica evidente a importância de pesquisas que apresentem ferramentas para o auxílio na identificação de oportunidades de melhorias no que se refere à confiabilidade de entrega. A identificação de oportunidades de melhorias requer uma estrutura de diagnóstico do desempenho da situação atual. No entanto, dependendo do problema de desempenho a ser diagnosticado, um arcabouço teórico com base no domínio de conhecimentos específicos da científica é necessário. Este trabalho apresenta o framework desenvolvido por Soepenberg et al. (2012c), que se baseia nos conceitos de WLC. Tal framework consiste em uma estrutura para o processo de diagnóstico do desempenho da confiabilidade de entrega, que permite navegar a partir do desempenho alcançado para as causas subjacentes relacionadas ao PCP. O objetivo do presente trabalho é apresentar o WLC, bem como as ferramentas de diagnóstico com o propósito de elucidar suas aplicabilidades através do framework desenvolvido por Soepenberg et al. (2012c) em um contexto real através de um estudo de caso. Os resultados do estudo de caso apontaram que o framework é um importante instrumento de diagnóstico devido à precisão para a determinação das causas de atraso das ordens relacionadas às decisões de PCP. A aplicação do framework identificou que a falta de peças é o fator mais impactante nos atrasos, porém a mesma não é uma causa relacionada somente as decisões de PCP da empresa, mas a fatores externos que não podem ser controlados pela empresa. Outro resultado obtido é a constatação de que a maioria das ordens é concluída antes das datas estabelecidas. Esse fato é resultado da falta de acurácia na determinação das datas de entrega e do erro na estimativa da capacidade a ser utilizada para a manutenção de cada part number, cuja responsabilidade dessas atividades é do PCP.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-06-14T17:48:43Z No. of bitstreams: 1 DissGMC.pdf: 11145534 bytes, checksum: 202d7605d259f2340c8be026f93609f8 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-19T18:25:48Z (GMT) No. of bitstreams: 1 DissGMC.pdf: 11145534 bytes, checksum: 202d7605d259f2340c8be026f93609f8 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-19T18:25:58Z (GMT) No. of bitstreams: 1 DissGMC.pdf: 11145534 bytes, checksum: 202d7605d259f2340c8be026f93609f8 (MD5) / Made available in DSpace on 2017-06-19T19:10:25Z (GMT). No. of bitstreams: 1 DissGMC.pdf: 11145534 bytes, checksum: 202d7605d259f2340c8be026f93609f8 (MD5) Previous issue date: 2017-01-31 / Não recebi financiamento / Commercial aircrafts are understood as the safest transportation when data such as operation hours by accident or incident are analyzed. According to studies conducted by the US National Security Council (NSC), the odds of a fatal crash is about one in eleven millions – which is smaller than elevators’ fatal failures, since commercial aircrafts operate for longer distances and time. Nevertheless, in order to aircraft products reach the highest reliability levels before start flying, it is necessary they to be extensively tested, ensuring that projects, materials and production methods comply to international safety requirements. This assessment process is called Aircraft Certification and is recognized as the most complex, time and money consuming of aircraft production, particularly for the civil aviation aircrafts. In Brazil, this activity is under the accountability of a Federal Agency, which regulates an important sector of the national economy. Therefore, the main objective of the present study was to analyze the Brazilian Aircraft Certification Process and assess its possible impacts in the competitiveness of national aerospace industry. Research information is based on a wide bibliographical review, regarding certifying process and national aerospace industry, followed by a field research, conducted through semi-structured interviews focused on understanding the perceptions of big companies, small and medium enterprises (SME) and Aircraft Certification Authority on this subject. Analysis of collected data indicate the Certifying Process is not capable by itself to influence the industrial development, but the structures of the organizations evolved on the Certification Process and the lack of interest and public policies may limit the competitiveness of the national aerospace industry. Opportunities which can contribute to the organizations and to the studied processes were identified, but current circumstances lead to the conclusion that in short and medium time it is going to be very difficult to a big Brazilian aerospace company to succeed in reaching the levels of the two major global aircraft builders, as well as for the small and medium enterprises in building bigger aircrafts, following the steps of the big companies. / Aeronaves comerciais são conceituadas como o meio de transporte mais seguro, quando são considerados os índices horas de utilização por acidentes ou incidentes. Conforme pesquisas realizadas pela instituição National Security Council (NSC) dos Estados Unidos, a chance de ocorrer um evento fatal é de apenas uma em 11 milhões, superando inclusive o elevador, pois as aeronaves percorrem distâncias muito superiores e com tempo de utilização muito maior. Entretanto, para que os produtos aeronáuticos cheguem aos mais altos níveis de confiabilidade, antes de voar, é necessário que sejam testados de forma exaustiva, demonstrando que os projetos, materiais e métodos de produção atendam a requisitos de segurança convencionados internacionalmente. Este processo obrigatório de avaliação é chamado de Certificação Aeronáutica, sendo considerado uma das fases mais complexas, demoradas e caras da produção aeronáutica, principalmente para aeronaves destinadas a aviação civil. No Brasil esta atividade é gerenciada por uma agência reguladora federal, cuja atuação influencia um importante segmento da economia nacional. Desta forma o objetivo da presente pesquisa foi estudar o processo de Certificação Aeronáutica no Brasil e avaliar os possíveis impactos na competitividade da indústria aeronáutica nacional. A exploração das informações de pesquisa deu-se inicialmente por meio de uma revisão bibliográfica para contextualização do processo certificatório e do cenário da indústria aeronáutica nacional, posteriormente realizou-se uma pesquisa de campo, aplicando entrevistas semi-estruturadas visando entender as percepções da indústria de grande porte, de pequeno porte e da Organização de Certificação Aeronáutica, sobre a questão. Os resultados obtidos apontam que não é propriamente o processo de Certificação um possível influenciador no desenvolvimento industrial, mas são as estruturas das organizações envolvidas na Certificação e a ausência de interesse e políticas públicas que podem limitar à competitividade do segmento aeronáutico nacional. Foram identificadas oportunidades e possibilidades que podem contribuir às organizações e aos processos estudados, porém nas circunstâncias atuais conclui-se que a curto e médio prazo, dificilmente uma indústria brasileira de grande porte conseguirá atingir os patamares dos dois maiores fabricantes de aeronaves do mundo, tanto quanto dificilmente a indústria nacional de pequeno porte conseguirá produzir aeronaves maiores e trilhar os caminhos dos grandes fabricantes.

Les systèmes de communication de l'aviation civile sont soumis à une demande de capacité toujours croissante pour répondre à l'augmentation du nombre de vols et au développement de nouveaux services. Dans ce contexte, les réseaux ad hoc aéronautiques, aussi appelés AANET (Aeronautical Ad-hoc NETwork), sont étudiés comme une solution de communication innovante et complémentaire des systèmes existants. Un AANET est un réseau ad hoc dont les nœuds sont des avions. Il exploite les capacités de communication directe entre les nœuds pour transmettre des données au delà de la portée radio en utilisant une chaîne de nœuds relais. Cette thèse a pour objectif de proposer des solutions à deux problématiques complexes dans les réseaux ad hoc en tenant compte des contraintes spécifiques aux AANET : la gestion de l'accès au canal et le routage des données. La faisabilité de tels réseaux a déjà été démontrée dans la littérature, et une architecture de communication basée sur le CDMA (Code Division Multiple Access) a été proposée afin de pouvoir discriminer des transmissions concurrentes entre plusieurs utilisateurs. Cependant, aucune méthode d'attribution des codes d'étalement n'a été spécifiée. Pour résoudre ce problème dans un réseau à grande échelle tel qu'un AANET, nous proposons d'améliorer une méthode existante : le RP-CDMA (Random Packet CDMA). Nous présentons ensuite le protocole de routage novateur que nous avons conçu : NoDe-TBR (Node Density TBR). Dans le paradigme de routage TBR (Trajectory Based Routing), les paquets sont transférés de manière à suivre un chemin géographique appelé geopath, spécifié par l'émetteur. Nous avons conçu à travers NoDe-TBR une méthode pour déterminer ces chemins dans un AANET. Dans ce protocole, les geopath sont calculés en tant que géodésiques qui prennent en compte la densité effective des avions. Cette approche a été choisie car elle devrait présenter les avantages des algorithmes de routage géographique (très faible signalisation générée) tout en étant robuste aux conditions spécifiques rencontrées dans les AANET (mobilité, densité d'avions non uniforme). Afin d'évaluer les performances des solutions que nous proposons, nous avons développé des modèles avec le simulateur Omnet++. Nous avons utilisé une approche basée sur le rejeu de trajectoires réelles d'avions afin de rendre compte au mieux de la diversité des contraintes qui s'y appliquent. Le trafic de données simulé représente des communications bidirectionnelles entre des avions en vol et des services de contrôle au sol. Nos simulations mettent en évidence que les modifications que nous avons apportées au RP-CDMA améliorent les performances globales du système. Ces simulations montrent aussi que l'algorithme NoDe-TBR est sensiblement plus performant que des algorithmes de routage classiques en termes de délai et de joignabilité, tout en générant un volume négligeable de messages de signalisation. / The communication systems used in civil aviation are subject to an ever increasing capacity demand because of the air traffic growth and the development of new services. In this context, the AANETs (Aeronautical Ad-hoc NETworks) are studied as an innovative communication solution that would complement existing systems. An AANET is an ad hoc network in which the nodes are aircraft. It makes use of direct inter-aircraft communications to transmit data beyond the radio range by using a chain of relays. The objective of this thesis is to propose a solution to two complex problematics present in AANETs : the channel access management and the routing. Previous studies have shown the feasibility of such networks, and a communication architecture based on CDMA (Code Division Multiple Access) has been proposed in the literature. The CDMA allows concurrent receptions between users. However, no spreading code assignment method have been specified. In order to solve this problem on large scale networks such as AANETs, we propose to improve an existing method : the RP-CDMA (Random Packet CDMA). We then describe the innovative routing protocol that we have designed: NoDe-TBR (Node Density TBR). In the TBR (Trajectory Based Routing) paradigm, the packets are forwarded along a geographical path (geopath), specified by the sender. We specify through NoDe-TBR a method to compute these paths. In this protocol, the geopaths are computed as geodesics which take into account the actual node density. This approach has been selected because it should have the benefits of geographic routing (very low overhead) while being robust to the specific conditions encountered in AANETs (mobility, uneven aircraft density). To assess the performances of our propositions, we have developed models for the simulator Omnet++. We have used an approach based on the replay of actual aircraft trajectories in order to take into account the variety of constraints applied to the movements of the aircraft. The simulated data traffic represents bidirectional communications between aircraft and ground stations. Our simulations shows that the modification we propose for RP-CDMA improve the overall performances of the system. The simulations results also shows that NoDe-TBR outperforms more classical routing methods in terms of reachability and delay, while generating less overhead.

Orientador: Auteliano Antunes dos Santos Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-20T21:40:56Z (GMT). No. of bitstreams: 1 Rodovalho_TainaGomes_M.pdf: 3540461 bytes, checksum: 3c0c4958dda8a145125013006521864f (MD5) Previous issue date: 2012 / Resumo: O uso dos materiais compósitos pela indústria aeronáutica tem ganhado cada vez mais espaço, sendo, portanto, de grande importância o conhecimento de suas características tanto na fase de projeto quanto na de manutenção. A presença de falhas e tensões não identificadas durante o processo de fabricação ou de manutenção pode significar perdas sociais, ambientais e econômicas. Dentre os métodos de medição e de inspeção não destrutiva em compósitos, os ultrassônicos mostraram-se mais eficientes por não depender da estrutura cristalina do material como os métodos de difração de nêutrons e de raios-X. Assim, determinar o perfil de resposta da velocidade de propagação da onda ultrassônica longitudinal criticamente refratada (LCR) em função da tensão aplicada para esse material, e avaliar se esta é linear e replicável, torna-se uma tarefa importante para posterior análise de tensões residuais. Neste trabalho analisa-se as influências da direção das fibras e da temperatura na velocidade de propagação das ondas ultrassônicas longitudinais, visando avaliar, posteriormente, o perfil acustoelástico dos laminados unidirecionais carbono/epóxi (HexTow® AS4 /Hexply® 8552) com direções de fibra a 0º, 45º e 90º. Para analisar os fatores de influência foram executados os testes de análise da variância (ANOVA) com distribuição F e o teste de Tukey, para comparar os níveis dos fatores. Os resultados mostraram que todos os fatores analisados influenciam na medida da velocidade da onda longitudinal, sendo a direção das fibras o fator de maior influência. Os resultados obtidos permitirão, em trabalhos futuros, a construção de modelo que permita obter a resposta de laminados quasi - isotrópicos empregados na indústria aeronáutica para diferentes sequências de empilhamento / Abstract: The use of composite materials for aerospace industry has gained more space and is therefore of great importance the knowledge of its characteristics, both in the design and in the maintenance. The presence of faults and unidentified strains during manufacturing or maintenance process can mean social, environmental and economic losses. Within the methods of measurement and nondestructive inspection of composites, ultrasonic methods have shown to be more efficient because they do not depend on the crystal structure of the material as the methods of neutron diffraction and X-rays. Thus, determining the response profile of the propagation velocity of longitudinal critically refracted (LCR) waves as a function of stress applied to the material, and to evaluate whether this is linear and repeatable, has become an important task for later analysis of residual stresses. This study analyzes the influences of fiber direction and temperature on the speed of propagation of longitudinal ultrasound waves, to evaluate further the profile acustoelastics of laminated unidirectional carbon/ epoxy (HexTow ® AS4 / Hexply ® 8552) with directions fiber at 0 °, 45 and 90. To analyze the factors of influence were performed the analysis of variance (ANOVA) test with distribution F and Tukey's test to compare the levels of factor. The results showed that all analyzed factors influences in the measure of longitudinal wave velocity, being the direction of the fibers the factor of most influence. The results allow the construction of a model, in future works, to achieve the response of laminated quasi - isotropic employed in the aviation industry for different stacking sequences / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestra em Engenharia Mecânica

Flight test telemetry environments can be particularly challenging due to RF shadowing, interference, multipath propagation, antenna pattern variations, and large operating ranges. In cases where the link quality is unacceptable, applying multiple receiving assets to a single test article can significantly improve the overall link reliability. The process of combining multiple received streams into a single consolidated stream is called Best Source Selection (BSS). Recent developments in BSS technology include a description of the maximum likelihood detection approach for combining multiple bit sources, and an efficient protocol for providing the real-time data quality metrics necessary for optimal BSS performance. This approach is being standardized and will be included in Appendix 2G of IRIG-106-17. This paper describes the application of this technology and presents performance results obtained during flight testing.

Altimeter measures atmospheric air pressure and counts actual model altitude from it. Then sends data to ground module, which shows them on display. Ground module contains USB interface for connecting to PC. It enables upload of flight data and opportunity to show them in graphical representation.

This diploma thesis provides an overview and basic principles of satellite communication systems. Further is description of specific aerial satellite communication system ARINC 791. The practical part includes proposals of the system for automated verification targeting functionality of an air satellite antenna, which has been carried out in Honeywell laboratory conditions. The selected implementation is realized and used for automated verification targeting functionality of an air satellite antenna. The results are graphically evaluated.